This document describes SLMs having improved image quality, modulation speed, and power handling. The improved SLMs are useful in lithographic writers and other patterning applications. An SLM with high speed and high power handling gives a lower system cost since a single SLM can replace several SLMs as known in the art. The highest known throughput in prior 1D SLMs is 2 billion gray-scale pixels per second. The technology disclosed enables SLMs with a throughput of 20-30 billion pixels per second.
What we call one-dimensional SLMs have been used for computer displays and for lithography. By “one-dimensional SLM” we mean a single row of controllable elements, such as in early versions of Texas Instruments' “digital light processor” or DLP, which is used in projectors, televisions and other applications. Another example of a one-dimensional SLM is the grating light valve or GLV devices from Silicon Light Machines.
SLMs of various configurations have been produced by Texas Instruments and Xerox (1D deformable mirror arrays for xerographic printers), Silicon Light Machines (Grating Light Valve, or GLV, displays photo setting and lithography), Samsung (Spatial Optical Modulator, or SOM, for laser displays), KODAK (Grating Electro-Mechanical System, or GEMS, for laser displays) and Micronic Laser Systems (lithography). It is worth noting that 1D and 2D SLMs are not replacements for each other, but are used in different architectures. In particular, they are illuminated with different types of light sources. A 1D SLM is typically used in a scanning mode with continuous or quasi-continuous (high-frequency pulsing e.g. mode-locked) light sources, while 2D SLMs use a low-frequency pulsed laser (e.g. an excimer laser) to realize the full inherent data rate of the 2D array.
An opportunity arises to improve on SLM design in ways that potentially improve operating spread, reduce surface damage to mirrors, permit switching array banks of elements without replacing the SLM, and/or extending the life of an SLM.